﻿Three new species of Quadrastichus Girault (Hymenoptera, Eulophidae) from China with a key to Chinese species

﻿Abstract Six species of Quadrastichus Girault (Eulophidae: Tetrastichinae) from China are reviewed, including three new species: Q.longisetasp. nov., Q.flavomaculatussp. nov., Q.longiscapussp. nov. and one new country record, Q.vacuna (Walker, 1839). New distributional data for Q.anysis (Walker, 1839) and Q.sajoi (Szelényi, 1941), and a key to the Chinese species of Quadrastichus based on females, are included.

Quadrastichus species are widely distributed and can be recognized by the following combination of characteristics: submarginal vein (SMV) with a single dorsal seta (occasionally two setae in aberrant specimens of Q. vacuna); mid lobe of mesoscutum usually with one adnotaular seta (two or three setae in a few species and five adnotaular setae at most in Q. erythrinae); scutellum with submedian grooves; propodeal spiracles close to metanotum; ovipositor sheaths not, or slightly, extending beyond tip of gaster (Graham 1991).When distinguishing different genera, Quadrastichus is similar to Oomyzus in having only one dorsal seta on the SMV, however, Quadrastichus species have all funicular segments longer than broad compared to species of Oomyzus.Actually, this genus is most similar to Aprostocetus, especially the subgenus Ootetrastichus, in the reduced number of adnotaular setae and slender body, however, Quadrastichus species have only one dorsal seta on ZooKeys 1187: 169-188 (2023), DOI: 10.3897/zookeys.1187.111723 Wen-Jian Li & Cheng-De Li: Three new species of Quadrastichus Girault from China the SMV and are non-metallic or weakly metallic compared to species of the subgenus Ootetrastichus.
In this paper, we add four more species, including three new species and one new country record to the Chinese fauna.Also, a key to Chinese species is given based on females.

Materials and methods
Specimens were collected by sweeping, yellow-pan trapping and were dissected and mounted (dorsal side up) in Canada Balsam following the method described by Noyes (1982) or glued to triangular cards.Photographs were taken with a CCD digital camera attached to an Olympus BX51 compound microscope (slide-mounted specimens) and Leica M205C microscope (card-mounted specimens).Slide-mounted specimen measurements were made using an eye-piece reticle with an Olympus CX21 compound microscope.Card-mounted specimen measurements were taken using an eye-piece reticle with a Motic SMZ168-B dissecting microscope.In the descriptions below, measurements/ ratio in brackets after measurement/ratio ranges refer to the holotype.The terminology follows Graham (1987) and Gibson et al. (1997).All specimens studied in this paper are deposited in the insect collections of Northeast Forestry University (NEFU) and Yancheng Teachers University (YCTU).Diagnosis.Female.Body mainly dark brown with weak metallic reflections.Antenna with scape just reaching, not extending above vertex, 4.3-4.6×as long as broad; pedicel longer than F1; funicle slender and thickening at base of each each funicular segment, F1 shortest, F2 shorter than or as long as F3, clava distinctly longer than F2 and F3 combined, 6.0-7.0× as long as broad, terminal spine as long as C3, flagellum with numerous curved long setae on each segment.Male.Body black with bluish metallic reflection.Antenna with plaque 0.5× the length of scape, flagellum with numerous whorls of long setae at base of each segment, especially on funicular segments.

Key to Chinese species of Quadrastichus Girault (females)
Following Graham (1991), Q. longiseta should belong in the anysis-group as follows: body black with yellow markings; frons with median area but without median carina; malar sulcus curved.This species is similar to Q. anysis (Walker), but can be separated from this species by the following combination of characters: pedicel longer than F1 (vs as long as); F1 shortest, F2 shorter than or as long as F3 (vs F1-F3 subequal in length); clava distinctly longer than F2 and F3 combined, 6.0-7.0× as long as broad (vs clava as long as F2+F3, 3.2-3.9×as long as broad).
Gastral petiole (Fig. 6) present and transverse.Gaster ovate (Fig. 6), 1.5-1.8×(1.5×) as long as broad, slightly longer and broader than mesosoma, slightly shorter than head and mesosoma combined; each gastral tergite with long erect setae on dorsal surface; each cercus with 3 setae, the longest seta 2.3× as long as the second longest seta; ovipositor 0.7× as long as gaster, ovipositor sheaths extending slightly beyond the tip of gaster; tip of hypopygium situated slightly before middle of gaster.
Etymology.The epithet longiseta refers to the long setae on the antennae in both sexes.Diagnosis.Female.Gaster with a yellow spot at base dorsally (Figs 17,18).Frons with a median line.Antenna slender with pedicel distinctly shorter than each funicle segment.Mid lobe of mesoscutum with median line distinct.Propodeum with median carina and paraspiracular carinae distinct.Male.Unknown.

Quadrastichus
Quadrastichus flavomaculatus is similar to Q. anysis (Walker), but can be separated from this species by the following combination of characters: pedicel distinctly shorter than F1 (vs as long as); each funicle segment more than 2.5× as long as broad (vs 2.0-2.2×);mid lobe of mesoscutum with a distinct median line (vs weak or absent); gaster 2.7-3.4× as long as broad (vs 1.2-1.8×).

Quadrastichus vacuna
Comments.Graham (1991) reported that this species occasionally has two dorsal setae on the SMV.However, all specimens we examined only have one dorsal seta on the SMV.pedicel 2.0-2.3× as long as broad; F1-F3 equal in length, each 2.0-2.2× as long as broad; clava 3.0-4.0×as long as broad.Mid lobe of mesoscutum with 1 adnotaular seta on each side situated in posterior half, without median line.Propodeum with median carina.Fore wing 2.0-2.1× as long as broad, costal cell narrow, shorter than MV; MV 3.0-4.0×STV; SMV with 1 dorsal seta; speculum small.
Comments.Graham (1991) reported that this species was variable in color.The colors of the specimens we examined are also not completely consistent, mainly in the yellow area of gaster, extending from the base to basal half.Diagnosis.Female.Malar sulcus (Fig. 35) distinctly curved, with a large subtriangular fovea below eye.Pronotum (Figs 35,38) with 4 coarsely reticulate yellowish areas, remaining surface dark.Mid lobe of mesoscutum with 2-3 adnotaular setae on each side.Fore wing (Fig. 39) narrow, 2.2-2.5× as long as broad; MV 3.5-4.0×STV; SMV with 1 dorsal seta; speculum small, marginal setae long.
Male.Unknown for Chinese material.
Comments.This species can be distinguished from other Quadrastichus species by the pronotum with four coarsely reticulate yellowish areas, with the remaining surface dark.